I have two new broms that have small black dots that I think are scale and I've read that using a hose to knock them off works. I don't have access to the hose right now (sprinklers) so I was wondering if I could use the kitchen sink sprayer or my handheld shower head?
I had scale once and found if I sprayed them hard with water this does work. I put gloves on and scratched off each one that i could reach. Pay close attention to those leaves near the trunk. You may have to do this several times, so don't give up. I think I even used some dish detergent in water also.
In your case I would use the kitchen sink. My spouse is use to seeing plants, dirt, and rocks in the sink.